From abd3dd4e2e37f04c765f1396aedd00885c6cc02a Mon Sep 17 00:00:00 2001
From: Thom Lamb <thomlamb@gmail.com>
Date: Tue, 25 Aug 2026 15:06:15 -0500
Subject: [PATCH] feat(filters): add tag and price dimensions (#188)

---
 .../components/filters/standardDimensions.tsx | 142 +++++++++++++++++-
 frontend/tests/unit/filterDimensions.test.ts  |  52 ++++++-
 2 files changed, 192 insertions(+), 2 deletions(-)

diff --git a/frontend/src/components/filters/standardDimensions.tsx b/frontend/src/components/filters/standardDimensions.tsx
index 3ea2ef0..a4ebefb 100644
--- a/frontend/src/components/filters/standardDimensions.tsx
+++ b/frontend/src/components/filters/standardDimensions.tsx
@@ -1,6 +1,15 @@
 import TreeSelect from 'antd/es/tree-select';
 import Empty from 'antd/es/empty';
-import { buildCategoryTree, categoryPath, toCategoryTreeData } from '../../filters';
+import Select from 'antd/es/select';
+import Tag from 'antd/es/tag';
+import Slider from 'antd/es/slider';
+import InputNumber from 'antd/es/input-number';
+import {
+  buildCategoryTree,
+  categoryPath,
+  formatPriceRange,
+  toCategoryTreeData
+} from '../../filters';
 import type { FilterDimension } from './dimension';
 
 /**
@@ -50,3 +59,134 @@ export const categoryDimension: FilterDimension = {
         })
     }))
 };
+
+export const tagDimension: FilterDimension = {
+  key: 'tag',
+  placement: 'drawer',
+  // AND, deliberately the opposite of the category rule above.
+  heading: 'Tags — must have all of these',
+
+  render: ({ tags, filters, onChange }) => {
+    // The Select is handed ids, so a colour has to be looked up rather than
+    // carried along with the value.
+    const colours = new Map(tags.map((tag) => [tag.id, tag.color]));
+    return tags.length ? (
+      <Select
+        mode="multiple"
+        showSearch
+        optionFilterProp="label"
+        allowClear
+        placeholder="Any tags"
+        style={{ width: '100%' }}
+        aria-label="Filter by tags"
+        value={filters.tagIds}
+        onChange={(tagIds: number[]) => onChange({ ...filters, tagIds })}
+        options={tags.map((tag) => ({ value: tag.id, label: tag.name }))}
+        tagRender={({ value, label, closable, onClose }) => (
+          <Tag
+            color={colours.get(Number(value))}
+            closable={closable}
+            onClose={onClose}
+            // antd's default, which this renderer replaces: without it the pill
+            // swallows the mousedown and reopens the list.
+            onMouseDown={(event) => {
+              event.preventDefault();
+              event.stopPropagation();
+            }}
+            style={{ marginInlineEnd: 4 }}
+          >
+            {label}
+          </Tag>
+        )}
+      />
+    ) : (
+      <Empty image={Empty.PRESENTED_IMAGE_SIMPLE} description="No tags yet" />
+    );
+  },
+
+  chips: ({ tags, filters, onChange }) =>
+    filters.tagIds.map((tagId) => {
+      const tag = tags.find((candidate) => candidate.id === tagId);
+      return {
+        key: `tag-${tagId}`,
+        label: tag?.name ?? `Tag ${tagId}`,
+        // Undefined while /api/filters is loading, which the label fallback
+        // already covers — an uncoloured chip beats a missing one.
+        color: tag?.color,
+        onRemove: () =>
+          onChange({ ...filters, tagIds: filters.tagIds.filter((id) => id !== tagId) })
+      };
+    })
+};
+
+const centsToDollars = (cents: number | null): number | null => (cents === null ? null : cents / 100);
+const dollarsToCents = (dollars: number | null): number | null =>
+  dollars === null || Number.isNaN(dollars) ? null : Math.round(dollars * 100);
+
+export const priceDimension: FilterDimension = {
+  key: 'price',
+  placement: 'drawer',
+  heading: 'Price',
+
+  render: ({ priceRange, filters, onChange }) => {
+    const bounds = priceRange ?? { min_cents: 0, max_cents: 0 };
+    const sliderMax = Math.max(bounds.max_cents, bounds.min_cents + 100);
+    return (
+      <>
+        {/* Only where there are real bounds. Invented ones would misreport
+            where the prices actually are. */}
+        {priceRange && (
+          <Slider
+            range
+            min={bounds.min_cents}
+            max={sliderMax}
+            step={100}
+            value={[filters.minPriceCents ?? bounds.min_cents, filters.maxPriceCents ?? sliderMax]}
+            tooltip={{ formatter: (value) => `$${((value ?? 0) / 100).toFixed(0)}` }}
+            onChange={([min, max]) =>
+              // antd types the value as number[], so destructuring gives
+              // `number | undefined`. A range slider always emits both ends;
+              // the fallbacks are the bounds rather than nulls, which would
+              // read as "no filter" and widen the results.
+              onChange({
+                ...filters,
+                minPriceCents: min ?? bounds.min_cents,
+                maxPriceCents: max ?? sliderMax
+              })
+            }
+          />
+        )}
+        <div style={{ display: 'flex', alignItems: 'center', gap: 8, marginTop: 8 }}>
+          <InputNumber
+            aria-label="Minimum price"
+            prefix="$"
+            min={0}
+            style={{ width: '100%' }}
+            value={centsToDollars(filters.minPriceCents)}
+            onChange={(value) => onChange({ ...filters, minPriceCents: dollarsToCents(value) })}
+          />
+          <span style={{ opacity: 0.6 }}>to</span>
+          <InputNumber
+            aria-label="Maximum price"
+            prefix="$"
+            min={0}
+            style={{ width: '100%' }}
+            value={centsToDollars(filters.maxPriceCents)}
+            onChange={(value) => onChange({ ...filters, maxPriceCents: dollarsToCents(value) })}
+          />
+        </div>
+      </>
+    );
+  },
+
+  chips: ({ filters, onChange }) =>
+    filters.minPriceCents === null && filters.maxPriceCents === null
+      ? []
+      : [
+          {
+            key: 'price',
+            label: formatPriceRange(filters.minPriceCents, filters.maxPriceCents),
+            onRemove: () => onChange({ ...filters, minPriceCents: null, maxPriceCents: null })
+          }
+        ]
+};
diff --git a/frontend/tests/unit/filterDimensions.test.ts b/frontend/tests/unit/filterDimensions.test.ts
index 8704060..54a4655 100644
--- a/frontend/tests/unit/filterDimensions.test.ts
+++ b/frontend/tests/unit/filterDimensions.test.ts
@@ -1,7 +1,7 @@
 import { describe, it, expect } from 'vitest';
 import { EMPTY_FILTERS, ItemFilters } from '../../src/filters';
 import type { FilterContext } from '../../src/components/filters/dimension';
-import { categoryDimension } from '../../src/components/filters/standardDimensions';
+import { categoryDimension, priceDimension, tagDimension } from '../../src/components/filters/standardDimensions';
 import type { Category, Tag as ItemTag } from '../../src/api';
 
 const CATEGORIES: Category[] = [
@@ -55,3 +55,53 @@ describe('categoryDimension', () => {
     expect(state.latest?.categoryIds).toEqual([3]);
   });
 });
+
+describe('tagDimension', () => {
+  it('reports no chips when nothing is selected', () => {
+    const { ctx } = contextFor({});
+    expect(tagDimension.chips(ctx)).toEqual([]);
+  });
+
+  // #185: a tag looks like itself wherever it appears.
+  it('reports one chip per tag, carrying that tag colour', () => {
+    const { ctx } = contextFor({ tagIds: [10, 11] });
+    expect(tagDimension.chips(ctx).map((chip) => [chip.label, chip.color])).toEqual([
+      ['vintage', 'red'],
+      ['oak', 'lime']
+    ]);
+  });
+
+  it('falls back to the id, uncoloured, for a tag not loaded yet', () => {
+    const { ctx } = contextFor({ tagIds: [99] });
+    const [chip] = tagDimension.chips(ctx);
+    expect(chip?.label).toBe('Tag 99');
+    expect(chip?.color).toBeUndefined();
+  });
+
+  it('removes only the chip that was closed', () => {
+    const { ctx, state } = contextFor({ tagIds: [10, 11] });
+    tagDimension.chips(ctx)[0]?.onRemove();
+    expect(state.latest?.tagIds).toEqual([11]);
+  });
+});
+
+describe('priceDimension', () => {
+  it('reports no chip when neither end is set', () => {
+    const { ctx } = contextFor({});
+    expect(priceDimension.chips(ctx)).toEqual([]);
+  });
+
+  // One chip for the range rather than one per end: they are one filter, and
+  // removing half of it is not a thing anyone means.
+  it('reports a single chip when either end is set', () => {
+    expect(priceDimension.chips(contextFor({ minPriceCents: 1000 }).ctx)).toHaveLength(1);
+    expect(priceDimension.chips(contextFor({ maxPriceCents: 5000 }).ctx)).toHaveLength(1);
+  });
+
+  it('clears both ends when removed', () => {
+    const { ctx, state } = contextFor({ minPriceCents: 1000, maxPriceCents: 5000 });
+    priceDimension.chips(ctx)[0]?.onRemove();
+    expect(state.latest?.minPriceCents).toBeNull();
+    expect(state.latest?.maxPriceCents).toBeNull();
+  });
+});